<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>变量</title>
	<script>
		a = 1000;
		num = 2000;
		num = 100;
		num = "abc";

		num1=299;
		num2 = 300;
		sex = "男";
		age = 89;
		order_id = 465465456465;
		username = "学并思";
		a ="20";
		A = "30";
		// 姓名 = "xuebingsi"
		// document.write(num);
		// console.log(sex);

		// res = confirm("是否删除");

		// alert(res);
		// 
		res = prompt("你多大了");

		document.write(res);


	</script>
</head>
<body>
	
</body>
</html>